1. Field of the Invention
The present invention relates to a manufacturing method of a semiconductor light emitting element such as a light emitting diode (LED) and a laser diode (LD), and a semiconductor light emitting element manufactured by the same.
2. Description of the Related Art
Semiconductor light emitting elements such as LEDs and LDs each comprises a semiconductor laminated body formed of an n-type semiconductor layer, an active layer, and a p-type semiconductor layer that are laid one over another on a growth substrate of sapphire or the like, and electrodes for supplying to the active layer. Where the growth substrate has an insulation property, some areas of the semiconductor laminated body formed are etched using a method such as reactive ion etching until the n-type semiconductor layer is exposed, n-electrodes are formed on the n-type semiconductor layer, and p-electrodes are on the p-type semiconductor layer.
The choice for the growth substrate greatly affects the crystal quality of semiconductor layers especially in forming the semiconductor laminated body. Also, the conductivity, thermal conductivity, and light absorption coefficient of the substrate affect the electric, thermal, and optical properties of optical semiconductor elements, and hence a substrate on which semiconductor layers of good crystallinity can be grown does not necessarily satisfy all properties.
With respect to the above facts, LEDs or LDs of a so-called thin film structure have been proposed where the semiconductor laminated body being separated/removed from the growth substrate, electrodes are formed directly on the semiconductor laminated body that contributes to light emission (refer to, e.g., References 1 to 4 below). By the removal of the growth substrate, light absorption that occurs when light passes through the growth substrate is eliminated, and further the portion of light totally reflected at their interface due to the difference in refractive index between the semiconductor laminated body and the growth substrate can be reduced. Further, the use of a support substrate of higher thermal conductivity than the growth substrate that is bonded to the semiconductor laminated body improves the heat radiation property of semiconductor light emitting elements. A laser lift-off (LLO) method is used to remove a translucent growth substrate of sapphire or the like.
Reference 1: International Publication Pamphlet WO98/14986
Reference 2: Japanese translation of PCT international application publication No. 2005-516415
Reference 3: Japanese Patent Application Laid-Open Publication No. 2000-228539
Reference 4: Japanese Patent Application Laid-Open Publication No. 2004-172351